It is apparent that the Massive-MIMO (M-MIMO) technology has become a key enabling technology for future wireless communication systems, particularly in the fifth generation (5G) wireless systems. M-MIMO represents a paradigm shift in the way of thinking with regards to antenna and signal processing theory and engineering. Basically, the more antennas an array is equipped with, the more degrees of freedom the propagation channel can have, and the better performance in terms of capacity and link reliability. However, the performance of M-MIMO systems strongly depend on the properties of the antenna array and the propagation environment. When the number of antennas increases within a constrained space, a designer may confront many challenges. Among these is the mutual coupling effect, which is a major limiting factor to the performance of an M-MIMO antenna array. In practice, how to decrease mutual couplings between every pair of antenna elements in an antenna array, especially, an M-MIMO antenna array, in a finite area becomes a challenging issue.
It is desirable to provide an apparatus and a method for reducing mutual couplings in an antenna array.